1. Field of the Invention
The invention pertains to the field of paint spray atomizers.
2. The Prior Art
Two basic kinds of atomizer heads are known for paint spray guns. In air type spraying, the paint is fed to the exit nozzle almost without pressure and the atomizing as well as the transport to the workpiece is brought about by compressed air. In airless spraying, the paint is brought to the nozzle under a high pressure of, for example, 200 bar, so that the paint atomizes by itself when exiting from the nozzle. The paint reaches the workpiece without needing additional compressed air as a result of its kinetic energy. Recently, a third kind of atomizer head has become known. This is a combined air-airless spray head. The paint is maintained under high pressure but not as high pressure as in the case of purely airless paint sprayers. Compressed air is additionally used in lesser quantities of flow than in the case of purely compressed air paint sprayers.
In the combined method, pressures between 30 and 100 bar are used and the additional compressed air serves both to provide the atomization and to transport the paint to the workpiece. An atomizer head of this sort is taught by the German OS No. 2,422,597. One disadvantage of this known atomizer head is its complexity. Separate compressed air borings and orifices are necessary to produce atomization and to transport the paint to the article. A second disadvantage lies in the performance of the known atomizer head. At the edges of a fan-type paint spray, paint particles break away from the spray and are not directed to the workpiece.
There is thus a need for a simple, combined air-airless spray head, with improved paint deposition where fan-type sprays are being used.